Black rook in an active endgame position, often supporting a skewer or back-rank threat.

By Climbchess Research · 2026-05-08 · 3 min read · Updated May 8, 2026

SAE concept sae_13207 fires when black rook in an active endgame position, often supporting a skewer or back-rank threat.. It appears in 7 of 9,950 Climbchess puzzles (0.1%), spanning ELO 794–803 (median 796).

Free forever · no email · no signup · delete data anytime.

This page documents Black rook in an active endgame position, often…, one of 4,505 interpretable chess concepts extracted from Leela Chess Zero via sparse autoencoders. The full feature description from our SAE labelling pipeline reads:

Black rook in an active endgame position, often supporting a skewer or back-rank threat.

This pattern fires in 7 of our 9,950 tagged puzzles. The puzzles where it appears span ELO 794 to 803, with a median rating of 796. That distribution tells you whether this is a beginner cue or a master-level subtlety.

Pattern statistics

Related concepts

The five concepts most often co-firing alongside this one (Jaccard similarity over the puzzle co-occurrence graph) are:

• Black rook actively repositioned in a rook endgame, participating in a skewer… — similarity 0.429
• Active White rook threatening a decisive intrusion — 7th rank penetration or… — similarity 0.167
• Rook endgame where White has a positional or material advantage — connected… — similarity 0.154
• A square in the central pawn structure attacked by Black with no White… — similarity 0.060
• Rook endgame with active rook placement, often involving deflection… — similarity 0.045

Example puzzles

Below are 7 puzzles spanning the rating distribution. Each links to its own page with full move list and related concepts.

• Puzzle zTOrn — ELO 794, themes: crushing, endgame, short, side to move: Black
• Puzzle zTOrn_F — ELO 794, themes: crushing, endgame, short, side to move: White
• Puzzle zTOrn_M — ELO 794, themes: crushing, endgame, short, side to move: Black
• Puzzle y9L7e — ELO 796, themes: deflection, endgame, mate, side to move: White
• Puzzle y9L7e_F — ELO 796, themes: deflection, endgame, mate, side to move: Black
• Puzzle zmKu8 — ELO 803, themes: crushing, endgame, master, side to move: White
• Puzzle zmKu8_F — ELO 803, themes: crushing, endgame, master, side to move: Black

How to use this page

If you want to train this pattern, open the Climbchess trainer and filter for puzzles tagged with this concept. The trainer surfaces them at the right difficulty for your current rating, and tracks how often you spot the cue versus miss it. You can also browse the related concepts above to see neighbouring ideas in feature space.

Climbchess concepts are not heuristics written by a human author. Each one corresponds to a single direction in the residual stream of Leela Chess Zero that activates on a specific board feature, then was labelled by reading the top-activating positions. This makes the catalogue exhaustive (every Leela-detectable pattern is in here somewhere) and falsifiable (you can replay our extraction).